The selective separation of butene-1 from a c{11 {11 hydrocarbon mixture employing zeolites x and y

ABSTRACT

A process for the separation of butene-1 from other C4 monoolefins. A feed stream containing butene-1 along with another C4 mono-olefin is contacted with a crystalline aluminosilicate adsorbent selected from the X or Y zeolites containing barium or potassium cations at conditions to effect the selective adsorption of butene-1. The butene-1 adsorbed by the adsorbent is thereafter recovered as a purified product.

United States Patent 91 [111 3,723,561 Prieg nitz 1451 Mar. 27, 1973[54] THE SELECTIVE SEPARATION ()1:- 2,894,998 7/1959 Hess et al. ..5S/75BUTENEI FROM A C4 3,531,539 9 1970 Tidwell "260/677 HYDROCARBON MIXTURE2,971,993 2/ 1961 Kimberlin, Jr. et a1. ..260/677 AD EMPLOYING ZEOLITESX AND Y James w. Priegnitz, Elgin, 111.

Universal Oil Products Company, Des Plains, 111.

Filed: Dec. 1, 1971 Appl. No.: 203,837

Inventor:

Assignee:

US. Cl. ..260/677 AD, 260/677 A, 55/75, I 208/310 1111. c1 ..c07 11/12Field of Search ..260/677 A, 677, 677 AD; I 208/310; 55/75 ReferencesCited UNITED STATES PATENTS 9/1964 Etherington ..260/677 AD PrimaryExaminerDelbert E. Gantz Assistant Examiner-J. Nelson Attorney.larnes R.l-loatson, Jr. et al.

[ ABSTRACT 24 Claims, No Drawings- THE SELECTIVE SEPARATION OF BUTENE-lFROM A C IIYDROCARBON MIXTURE EMPLOYING ZEOLITES X AND Y BACKGROUND OFTHE INVENTION 1. Field of the Invention v The field of art to which thisinvention pertains is hydrocarbon separation. More specifically, theclaimed invention relates to a process for the separation of bul tene-Ifrom a feed mixture containing other C monoolefins using a crystallinealuminosilicate.

2. Description of the prior Art Crystalline aluminosilicates are knownin the art to be useful for separating hydrocarbons. Particularly someof the Type X or Type Y zeolites have been disclosed which relate to theseparation of olefins from paraffmic hydrocarbons and the separation ofbutene-l from isobutylene (see U.S. Pat. No. 3,531,539, Class 260-677).The present invention relates to the separation of mono-olefin isomersand in particular the separation of butene-l from the feed mixture whichcontains other C, mono-olefinic hydrocarbons.

In comparing the various C mono-olefinic hydrocarbons, namely butene-l,trans and cisbutene-2 and isobutylene it is found that butene-l has thelowest motor octane of the group. It is preferable to remove thiscomponent from olefinic mixtures which will end up as direct componentsto gasoline fuels. The use of this process allows the separation ofbutene-l from the other C mono-olefins and allows a higher octaneolefinic component to be utilized. Additional advantages of this processreside in the special chemical uses in which the butene-l material isdesired in a relatively high purity state. Because of the fact that somechemical process butene-i is the preferred feed stock as compared tothe-other mono-olefins, the process of this invention may be utilized toseparate butene-l from butene-2 and/or isobutylene. Additionaladvantages can be obtained by concentrating the nonselectively adsorbedcomponent, namely, isobutylene or butene-2 so it can' be recovered in arelatively purified state. Another advantage found in the process of Ithis invention is the relative inactivity of the adsorbent with respectto dimerization of the feed stock components and isomerization ofbutene-l to other olefins, namely transor cisbutene-2.

SUMMARY OF THE INVENTION This invention is a process for the separationof butene-l from a feed stock containing butane-2 or iso-butylene orboth. Feed stock is passed over an adsorbent comprising a Type X or TypeY zeolite containing potassium or barium cations to selectively adsorbbutene-l from the feed stock.

DETAILED DESCRIPTION OF INVENTION oxygen atoms with spaces between thetetrahedra occupied by water molecules prior to partial or totaldehydration of this zeolite. The dehydration of the zeolite results incrystals interlaced with cells having molecular-dimensions. Thus, thecrystalline aluminosilicates are often referred to as molecular sieveswhen the separation which they effect is dependent essentially upondistinction between molecule sizes. In the process of this invention,however, the term molecular sieves is not suitable since the separationof isomers is dependent on electro-chemical attraction of differentisomer configurations rather than pure physical size differences in theisomer molecules.

In hydrated form, the crystalline aluminosilicates generally encompassthose zeolites represented by the formula in equation 1 below:

where M is a cation which balances the electrovalence of the tetrahedraand is generally referred to as an exchangeable cationic site, nrepresents the valence of the cation, w represents the moles of SiO andy" represents the moles of water. The cations may be any one of a numberof cations which will hereinafter be described in detail.

The Type -X structured and Type Y structured zeolites as used in thisspecification shall include crystalline aluminosilicates having a threedimensional interconnected cage structure and can specifically bedefined by U.S. Pat. Nos. 2,882,244 and 3,130,007. The terms Type Xstructured" and Type Y structured" zeolites shall include all zeoliteswhich have a general structure as represented in the above two citedpatents and specifically including those structures containing variouscations exchanged upon the zeolite. In the most limiting sense, theseterms refer to Type X and Type Y zeolites.

The Type X structure zeolites can be represented in terms of mole oxidesas represented by the formula in equation 2 below:

0.9i0.2M ,,,O:Al,O :2.5 iO.5SiO y H 0 (2) where M represents at leastone cation having a valence of not more than 3, n" represents thevalence of M and y is a value up to about 9 depending upon the identityof M" and the degree of hydration of the crystalline structure.

The Type Y structure zeolites can be represented in terms of the moleoxides for the sodium form as represented by the formula in equation 3below:

where w" is a value of greater than about 3 up to 8,

and y" may be any value up to about 9.

the soluble salts of the cation or cations desired to be placed upon thezeolite. The desired degree of exchange takes place before the sievesare removed about 1 percent to about 100 percent ofthe original cationspresent being replaced by the cation or cations desired to be exchangedupon the zeolite. By knowing the empirical formula including the silicato alumina ratio of the zeolite used, its water content and the typezeolite used, whether it be Type X or Type Y structured zeolite, and thepercentage or binder of any within the zeolite, it is possible tocalculate the percentage of ion exchange'taking place. Obviously, thepercentage of ion exchange which takes place can be represented in termsof the weight percent of the zeolite which contains a cation when theatomic weight of the cation and its valence are determined. Cations areplaced singly or in pairs upon the zeolite and in some instances, thepreferred cations may be present on the zeolite in high concentrationswith various relatively small amounts of other cations present. It ispreferred, however, to reduce the unpreferred cation contentto a pointwhere'that cation does not function to substantially alter theselectivity of the adsorbent for the component desired to be adsorbed.

Cations which can be placed on the zeolite adsorbent include the GroupIA, Group A, GroupVlll and the group [B metals of the Periodic Table ofThe Elements.

Other cations not mentioned may be present in small quantities. For thepurposes of this invention, cations to be used on the adsorbent shallinclude cations selected from the above-mentioned groups and with thelimitation that the cation utilized beselective towards butene-l fromthe other feed stock components. Preferably from the group containingthe above recited cations, potassium and barium are preferred andpotassium alone being especially preferred, since these two cationsselectively. adsorb butene-l from other feed stock components in ahighly selective manner.

Feed stocks which can be utilized in the process of this invention canbe derived from any of the refinery processes known to the art.Specifically, the feed stocks include C mono-olefinic hydrocarbons suchas butenel, isobutylene, transbutene-2 and cis-butene-Z. The termbutene-Z shall include both the cisand transisomer configuration of thathydrocarbon. Other materials can be present in the feed stock such aslarge quantities of paraffinic or naphthene substances and in someinstances low concentrations of aromatic hydrocarbons and othercontaminant substances such as the combined sulfur nitrogen compounds.It is preferred, however, to substantially reduce the quantity ofcomponents which would contribute to the deactivation of the adsorbentby blocking off the adsorptive site-passageways to feed stockcomponents.

In the separation art, the feed stock is generally broken down into twocomponents namely, an extract material and a raffinate material. Theextract material is the component of the feed stock which is selectivelyadsorbed by. the adsorbent and for purposes of this specification shallmean butene-l. Raffinate material shall include the components of thefeed stock which arenot selectively adsorbed by the adsorbent and shouldinclude for the purposes of this disclosure isobutylerie and thebutene-2 isomers. The raffinate may also include extraneous componentsmentioned above and the extract materials may also contain in someinstances small contaminant materials such as olefins or aromatics orcombined sulfur or nitrogen compounds. It is preferable when utilizingfeed stocks to use feed stocks which contain anywhere from about a fewpercent of butene-l and a few percent of total olefins up to feed stockswhich contain essentially pure concentrations of C olefins. Specificfeed stocks which can be utilized in the process of this inventioninclude a feed stock containing about 35 vol.% butene-l, 32.5 vol.%isobutylerie and 32.5 isobutane. Other feed stock compositions includefeed stocks containing approximately 21 vol.% butene-l, 21 vol.%isobutylene, l6% transbutene-2, 16% cis-butene-2 with remaining feedstock components comprising a butane component such as iso-butane ornormal butane. The feed stock can contain other paraffinic substanceshaving higher molecular weight such as heptene'or hexanes or octanes ornonanes orhigher molecular weight paraffins. It is preferred to utilizefeedstocks having more than about 15 vol.% total olefins.

Since it is desired to recover the extract stream in relatively purifiedform, it is desired'that a desorption operation remove the selectivelyadsorbed extract component from the adsorbent for recovery purposes.Basically, the desorption operation includes either the passing of a gasor hydrocarbon material over the adsorbent in the absence of mostraffinate material and the recovery of extract material by thereplacement of the purging of the extract material from the adsorbent.Specifically, desorbent materials which can be included in the processof this invention include higher weight olefins such as octene-l orlower molecular weight olefins, all of which are easily capable ofseparation from butene-l. Specifically, desorbents which containmixturesof normal olefins and isoparaffins are found to possess desiredqualities with respect to desorbing the extract material from theadsorbent.

In specific instances in which liquid operations take place, a preferreddesorbent for the butene-l separation includes a mixture of 20 vol.%octent-l and vol.% isooctane. Other desorbent materials can be used suchas aromatic hydrocarbons or paraffinic substances. Still other desorbentmaterialswhich are easily separated from butene-l include such readilyavailable gases as hydrogen or methane or in some instances steam orair, all of which can be used to purge the extract material from theadsorbent.

Adsorption conditions include temperatures from ambient up to about 350F. or higher. In some instances the 350 F. temperature may be too highas catalytic activity may be initiated at these temperatures, causingeither dimerization or isomerization of butene-l to another olefin whichmay not be desired. Pressures can be of any reasonable range anywherefrom vacuum up to many thousands of pounds. The

adsorbent does not have to overcome the vapor pressure differences inthe feed components which might have an adverse effect on selectivitywhen operating in the vapor phase. Adsorption conditions also includethe passing of the feed stock over an adsorbent material containing theselective cations. The adsorbent then selectively adsorbs butene-l inthe feed stock while leaving raffmate material such as butene-2 oriso-butylene in interstitial void spaces between the adsorbentparticles. Included within the definition adsorption conditions can be apurge step in which the raffinate material is either purged from theadsorbent by another hydrocarbon material or removed by a gas-purgingstep leaving an adsorbent containing essential butene-l at the selectiveadsorptive sites within the adsorbent particles.

Desorption conditions include the pressure temperature limitationsdescribed above for the adsorption conditions. Additionally, desorptionconditions include the passage of a desorbent material over theadsorbent after the adsorbent has contacted the feed stock.

Depending upon the processing scheme utilized, desorption conditions caninclude a gas purge at a higher temperature than adsorption conditionsand in conjunction with a reduced pressure. Using these type operations,butene-l can be easily recoveredfrom the adsorbent. Other desorptionconditions can include the passage of desorbent material as a liquidover the ad-. sorbent at conditions to effect the removal of butene-ifrom the adsorbent and replacement thereof on the adsorbent by thedesorbent material. The butene-l material is then recovered in admixturewith the desorbent material and is passed into a simple fractionating orseparating means in which pure butene-l and desorbent are recovered.Desorption conditions can include the removal or desorbent material fromthe adsorbent by purging operations. In these instances, the materialwhich is adsorbed upon the adsorbent can be removed by a gas purge orvacuum desorption step. The adsorbent can then be recontacted with feedstock at adsorption conditions.

The various flow schemes which can be utilized to effect the process ofthis invention include the relatively simple swing-bed operations inwhich one or more adsorbent beds are connected in a manner to allow adsorption and desorption operations to take place in each of the bedssimultaneously with the switching of feed stock and desorbent materialsbetween the individual adsorbent beds to effect the relativelycontinuous production of extract and raffmate materials. The process ofthis invention can also be effected using a single chamber in whichalternatestreams are passed through it; however, this process does notrender continuous production of extract material.

Especially preferred flow schemes are those generally referred to in theseparation art as fixed bed countercurrent flow processes in which afixed bed and a rotary valve are operated to effect a simulated movingbed operation. The general concept of this flow scheme is disclosed inU. S. Pat. No. 2,985,589 having as its inventor Donald B. Broughton andissued to Universal Oil Products Company.

In some instances, regeneration of the adsorbent may be necessary inorder to allow a continuous production of high quality extract material.Regeneration may be required when high quantities of aromatics orcontaminant material such as sulfur or nitrogen compounds are present onthe adsorbent in a concentration large enough to alter the selectivitybelow an optimum predetermined level. Specifically, regeneration caninclude the burning off of contaminant residues on the adsorbent or thecontacting 'of the adsorbent with steam or water or hydrocarbons atconditions to effectively flush off the contaminant materials from theadsorbent material. The adsorbent material can then be purgedof,regenerant and then reused. In some instances, regeneration may nottotally effectively regenerate theadsorbent but may be beneficialhowever.

EXAMPLEI In this example, tests were conducted on various crystallinealuminosilicate adsorbents to determine the ability to separatebutene-l, butane-2 and isobutylene. The adsorbents utilized consistedessentially of Type X crystalline aluminosilicates which had beenionexchanged with various cations prior to testing. All of theadsorbents utilized were from 20 to 40 mesh in particle size.

The equipment utilized in this experiment consists of an adsorbentvessel which contained the particular adsorbent being tested. Thechamber had inlet and outlet streams and was located within a heatcontrol means in order that the streams passing into and out of thechamber along with the adsorbent present chamber could be maintained ata constant temperature of about 50 C. Sufficient pressure was maintainedupon the system to maintain the feed and effluent in a liquid phase.

The procedure utilized for testing the adsorbent consisted of passingdesorbent material through the adsorbent chamber at a liquid hourlyspace velocity of about 1 to 1.2. Periodically, a feed sample wasinjected into thedesorbent stream passing into the adsorbent stream andallowed to pass through the chamber. The effluent from the adsorbentchamber was then passed into a gas chromatographic column which was ableto determine and plot the relative concentrations of the feed stockcomponents in the effluent stream as a function of time. After a feedpulse was passed through the adsorbent chamber, the adsorbent wasallowed to contact the adsorbent in the chamber to flush off anyremaining feed which had been adsorbed upon a sieve within the chamber.By utilizing my experience with chromatographic methods of separation,it was possible to determine from the chromatograph generated therelative selectivity and adsorptive capacity of an adsorbent withrespect to butene-l and the other C mono-olefins.

The feed stocks utilized throughout this experiment consisted of amixture of 21.43 vol.% butene-l 21.43 vol.% isobutylene,-l6.l9 vol.%trans-butene-2, 16.19 vol.% cis-butene-2 and 24.76 vol.% of isobutanewhich is used as a carrier and tracer agent.

The selectivity of an adsorbent tested is necessary to be defined inorder to determine the relative ability of an adsorbent toconcentratevarious feed stock components. The selectivity of an adsorbent isdefined as the ratio of concentrations of two components adsorbed on anadsorbent over the'ratio of the same two components in an unadsorbedphase surrounding the adsorbent particles. Specifically, the selectivityis defined as shown in equation 4 below Selectivity B (x/y) a/(x/y) b (4where the ratio of the two components X and Y determine the selectivity.Subscript a refers to the adsorbed composition while subscript b refersto the composition of the material which was surrounding the adsorbentparticles present in, the interstitial. void spaces of the adsorbent.

As can be seen from the above equation where the ratio of selectivity isgreater than unity for'two components, component X would be theselectively adsorbed component from the feed stock consisting ofcomponents X and Y. Where the selectivity would be less than unity, the.selectivity would be reversed and component Y as shown in the equationwould be the more selective component of the feed stock. As can be seenfrom the specific definition of selectivity used, it is a relativetermand can only be applied in relation to two components in afeedstock.

The adsorbents utilized in this experiment were essentially Type Xstructured crystalline aluminosilicates which contain approximately 20wt. percent of a binder material comprising aluminosilicate material.The binder was utilized to hold the crystalline aluminosilicate togetherand for all practical purposes did not affect theselectivity of theadsorbent.

The first adsorbent tested was essentially totally potassium-exchangedadsorbent. This adsorbent had a chemicalanalysis of approximately 44.7wt.% SiO 33.6 wt.% A1 3.8 wt.% Na O and 17.8 wt.% K 0. The aboveanalysis-was determined after the adsorbent had been subjected tocalcination at 500 for sufficient time to allow a constant weight of theadsorbent to be recorded. It is assumed that the above chemical analysisis on an adsorbent as essentially free of volatile material which wouldexclude water from the analysis. The adsorbent as tested was treated tocontain approximately 2 wt.% of water after it had been manufactured.The manufacturing procedure which was utilized to produce this sieve wasessentially an ion-exchange with a water soluble potassium salt on anoriginally sodium Type X zeolite. The selectivities determined forbutene-l with respect to the other feed components of the feed stockutilized were as follows: butene-l with respect to isobutyleneselectivity amounted to about 2.2; butene-l with respect to cis-butene-2selectivity was about 2.5; and, butene-l with respect to trans-butene-2selectivity was also approximately 2.5. As can be seen from theseresults, the adsorbent was selective towards butene-1 with respect toall of the feed components tested and isv preferable adsorbent for usein the claimed process.

EXAMPLE 11 In this example a second adsorbent was utilized to test theeffects of a barium and potassium exchanged Type X zeolite. The feedstock, apparatus and procedures utilized in this example were identicalto those utilized in Example I above. The adsorbent utilized in thisexample was the adsorbent used in Example I which had been additionallytreated with an aqueous barium solution. The X-ray analysis of thisadsorbent indicated that it contained approximately 11.3 wt.% bariumoxide and 13. 5 wt.% potassium oxide. This adsorbent was tested as theadsorbent for Example I was tested and yielded results which indicatethat it too was selective for butene-l with respect to isobutylene andbutene-2. Results of testing procedures indicates that the selectivityfor butene-l with respect to isobutylene was approximately 2.1 while theselectivity of butene-l with respect to both the butenes-Z wasapproximately 2.4. The selectivity for butene-l with respect to cisortrans-butene-Z was not determined for reasons not pertinent to thepresentation of this material.

As can be seen from the above examples, the potassium exchanged andbarium and potassium exchanged Type X zeolites were selective towardsbutene-l with respect to isobutylene and the transand cis-butene-Z.

EXAMPLE 111 In this example a stability test was run utilizing theadsorbent tested in Example 1. The adsorbent activity testing wasperformed utilizing 4 and 18-hour recycle time periods utilizing a freshfeed which continuously was passed over the adsorbent at a temperatureof about 15 C. and pressure sufficient to maintain liquid operations.The feed stream utilized for the stability testing consisted ofapproximately vol.% of heptane, 20 vol.% of heptene and 10 vol.% of afeed mixture which composition is described ,for the feed mixtureutilized in Examples I and II above. 7

The stability test' was run to determine if dimers form from the Colefins and to determine if the butene-l could be isomerized. Both the4-hour recycle and 18- hour recycle stability test indicated very slightproduction of heavier weight components-less than about 0. 1 and 0.5wt.% respectively for the 4 and 18-hour recycle period. Essentially allof the feed components present before recycle operations had startedwere present after completion of the testing which indicated that thepotassium X sieve as utilized in Example I is essentially inert towardsthe feed stock components utilized.

The above examples are utilized as preferred and specific embodiments ofthe process of this invention are not to be utilized to unduly limit theclaims nor the scope of disclosure presented herein.

I claim as my invention:

1. A process for the separation of butene-l from a feed mixturecontaining at least one other mono-olefin containing 4 carbon atoms permolecule, which process comprises the steps of:

i. contacting said feed mixture with a crystalline aluminosilicateadsorbent, selected from the group consisting of X and Y zeolitescontaining a cation selected from the group consisting of potassium andbarium at cationic sites within said zeolite, at adsorption conditionsto effect. the selective adsorption of butene-l by said adsorbent; and

ii. recovering said butene-l from said adsorbent.

tion conditions include a temperature within the range I of from aboutambient to about 300 F.

4. Claim 1 further characterized in that said adsorption conditionsinclude the liquid phase.

5. Claim 1 further characterized inthat said crystalline aluminosilicateis an X zeolite.

6. Claim 1 further characterized in that said crystallinealuminosilicate is a Y zeolite.

7. A process for separating butene-l from a feed mixture containingisobutylene, which process comprises the steps of:

i. contacting said feed mixture with a crystalline aluminosilicateadsorbent, selected from the group consisting of X and Y zeolitescontaining cations selected from the group consisting of potassium andbarium at cationic sites within said zeolite, at adsorption conditionsto effect the selective adsorption of butene-l by said adsorbent; andii. recovering said butene-l from said adsorbent. 8. Claim 7 furthercharacterized in that said crystalline aluminosilicate is an X zeolite.

9. Claim 7 further characterized in that said crystallinealuminosilicate is a Y zeolite.

10. Claim 7 further characterized in that said adsorption conditionsinclude a temperature within the range of from about ambient to about300 F.

11. Claim 7 further characterized in that said cation linealuminosilicate is a Y zeolite containingbarium.

l4. Claim 7 further characterized in that said crystallinealuminosilicate is a Y zeolite containing potassium. 15. Claim 7 furthercharacterized in that said crystalline aluminosilicate is an X zeolitecontaining barium.

l6. Claim 7 further characterized in that said crystallinealuminosilicate is an X zeolite containing potassiurn.

. 17. A process for separating butene-l from a feed mixture containingbutene-Z which process comprises the steps of:

i. contacting said feed mixture with a crystalline aluminosilicateadsorbent, selected from the group consisting of X and Y zeolitescontaining cations selected from the group consisting of potassium andbarium. at cationic sites within said zeolite, at adsorption conditionsto effect the selective adsorption of butene-l by said adsorbent; and

ii. recovering said butene-l from said adsorbent.

18. Claim 17 further characterized in that said crystallinealuminosilicate is an X zeolite.

l9. Claim 18 further characterized in that said cations are barium.

20. Claim 18 further characterized in that said cations are potassium.

21. Claim 17 further characterized in that said crystallinealuminosilicate is a Y zeolite. 22. Claim 21 further characterizedv inthat said cations are barium.

23. Claim 21 further characterized in that said cations are potassium. I

24. Claim 17 further characterized m that said adsorption conditionsinclude a temperature within the rangeof from about ambient to about 300F.

2. Claim 1 further characterized in that said feed contains mono-olefinsselected from the group consisting of cis-butene-2, trans-butene-2, andisobutylene.
 3. Claim 1 further characterized in that said adsorptionconditions include a temperature within the range of from about ambientto about 300* F.
 4. Claim 1 further characterized in that saidadsorption conditions include the liquid phase.
 5. Claim 1 furthercharacterized in that said crystalline aluminosilicate is an X zeolite.6. Claim 1 further characterized in that said crystallinealuminosilicate is a Y zeolite.
 7. A process for separating butene-1from a feed mixture containing isobutylene, which process comprises thesteps of: i. contacting said feed mixture with a crystallinealuminosilicate adsorbent, selected from the group consisting of X and Yzeolites containing cations selected from the group consisting ofpotassium and barium at cationic sites within said zeolite, atadsorption conditions to effect the selective adsorption of butene-1 bysaid adsorbent; and ii. recovering said butene-1 from said adsorbent. 8.Claim 7 further characterized in that said crystalline aluminosilicateis an X zeolite.
 9. Claim 7 further characterized in that saidcrystalline aluminosilicate is a Y zeolite.
 10. Claim 7 furthercharacterized in that said adsorption conditions include a temperaturewithin the range of from about ambient to about 300* F.
 11. Claim 7further characterized in that said cation is barium.
 12. Claim 7 furthercharacterized in that said cation is potassium.
 13. Claim 7 furthercharacterized in that said crystalline aluminosilicate is a Y zeolitecontaining barium.
 14. Claim 7 further characterized in that saidcrystalline aluminosilicate is a Y zeolite containing potassium. 15.Claim 7 further characterized in that said crystalline aluminosilicateis an X zeolite containing barium.
 16. Claim 7 further characterized inthat said crystalline aluminosilicate is an X zeolite containingpotassium.
 17. A process for separating butene-1 from a feed mixturecontaining butene-2 which process comprises the steps of: i. contactingsaid feed mixture with a crystalline aluminosilicate adsorbent, selectedfrom the group consisting of X and Y zeolites containing cationsselected from the group consisting of potassium and barium at cationicsites within said zeolite, at adsorption conditions to effect theselective adsorption of butene-1 by said adsorbent; and ii. recoveringsaid butene-1 from said adsorbent.
 18. Claim 17 further characterized inthat said crystalline aluminosilicate is an X zeolite.
 19. Claim 18further characterized in that said cations are barium.
 20. Claim 18further characterized in that said cations are potassium.
 21. Claim 17further characterized in that said crystalline aluminosilicate is a Yzeolite.
 22. Claim 21 further characterized in that said cations arebarium.
 23. Claim 21 further characterized in that said cations arepotassium.
 24. Claim 17 further characterized in that said adsorptionconditions include a temperature within the range of from about ambientto about 300* F.